I don't think its unreasonable to reach out to the manufacturer if your warranty period is only weeks or a few months expired. If I bought my camper in January and my warranty expired the following January, but I didn't get a chance to go camping until March and found that XYZ was broken, I might be a little upset if the manufacturer doesn't even consider covering or splitting cost with me.
Now, more than 2 or 3 months and I wouldn't expect much. A great company would be willing to work with a customer and help them out even after the warranty expired. If you had a great experience with your manufacturer, you would probably buy your next RV from them, wouldn't you? Then again, if you had a bad experience, you might avoid that manufacturer for the rest of your days.
When I think of all the money spent on advertising by car and RV companies, I have to wonder why more don't try to help customers and keep them loyal. You are directly advertising to a person who is already vested in your product and you are giving them a sense of ease.
Just my thoughts.